<!DOCTYPE html>
<html>

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>导航</title>
</head>

<body>

  <div class="nav">
    <div><a href="helloworld.html">HelloWorld</a></div>
  </div>
</body>

</html>